CD Projekt RED address the graphics in The Witcher 3 in a conversation with Eurogamer where they acknowledge that some effects shown in previews were cut from the release version of the game, particularly features shown in a 2013 gameplay trailer. Discussion of this apparently needed to be face-to-face, as CDPR flew someone out to Poland to confess about the changes. They include a bunch of details on an upcoming patch to improve visuals, as well as details on plans to allow further PC tweaking. They do admit that the console versions did cause some design compromises, but note that without the console editions, the game wouldn't exist at all. Here's the part where they address the graphics "downgrade":

Why did the graphics change?
"If you're looking at the development process," Iwinski begins, "we do a certain build for a tradeshow and you pack it, it works, it looks amazing. And you are extremely far away from completing the game. Then you put it in the open-world, regardless of the platform, and it's like 'oh shit, it doesn't really work'. We've already showed it, now we have to make it work. And then we try to make it work on a huge scale. This is the nature of games development."

It was captured PC footage, not pre-rendered, Badowski confirms, but a lot had to change. "I cannot argue - if people see changes, we cannot argue," Adam Badowski says, "but there are complex technical reasons behind it.

"Maybe it was our bad decision to change the rendering system," he mulls, "because the rendering system after VGX was changed." There were two possible rendering systems but one won out because it looked nicer across the whole world, in daytime and at night. The other would have required lots of dynamic lighting "and with such a huge world simply didn't work".

It's a similar story for environments, and their texture sizes and incidental objects. It was a trade-off between keeping that aspect of them or their unique, handmade design. And the team chose the latter. The data-streaming system couldn't handle everything while Geralt galloped around.

The billowing smoke and roaring fire from the trailer? "It's a global system and it will kill PC because transparencies - without DirectX 12 it does't work good in every game." So he killed it for the greater good, and he focused on making sure the 5000 doors in Novigrad worked instead.

"People are saying that 2013 was better but actually there's plenty of things that improved since 2013," Michal Platkow-Gilewski points out. "Size of the world, frames-per-second..."

"Yes!" realises Adam Badowski. "The game's performance: people say the game is well optimised. This is the first time for this company!" It's the first smile I've seen from him all interview.

Marcin Iwinski picks it up: "Maybe we shouldn't have shown that [trailer], I don't know, but we didn't know that it wasn't going to work, so it's not a lie or a bad will - that's why we didn't comment actively. We don't agree there is a downgrade but it's our opinion, and gamers' feeling can be different. If they made their purchasing decision based on the 2013 materials, I'm deeply sorry for that, and we are discussing how we can make it up to them because that's not fair.

"It's very important to stress: we are continuously working on the PC version, and we will be adding a lot of stuff, and there is more to come. We've proven it in the past that we support our games and we will be looking at the feedback and trying to make it better."